Breathable membrane for lens assembly having a second lens barrel positioned within and removeable from a first lens barrel

Abstract

Breathable membranes for lens assemblies are described. For example, a system may include a lens barrel having an inner channel extending from a first end of the lens barrel to a second end of the lens barrel. The lens barrel can include one or more inner lenses positioned within the inner channel. The lens barrel has a vent hole in a side of the lens barrel that extends from the inner channel to an exterior surface of the lens barrel. The system includes a membrane attached to the lens barrel and positioned to cover the vent hole. The membrane has pores large enough to permit nitrogen gas to flow through the membrane and the vent hole.

What is claimed is: 
     
       1. An apparatus comprising:
 a first lens barrel having an inner channel extending from a first end of the first lens barrel to a second end of the first lens barrel, the first end of the first lens barrel including exterior threading to facilitate connection of a retaining ring to the first lens barrel, the second end of the first lens barrel located inwardly of the exterior threading along a radius of the first lens barrel, the first lens barrel including one or more inner lenses positioned within the inner channel, wherein the first lens barrel has a vent hole in a side of the second end of the first lens barrel that extends from the inner channel to an exterior surface of the first lens barrel; 
 a second lens barrel positioned within the first lens barrel and including an outer lens and an additional inner lens, the second lens barrel removable from the first lens barrel to facilitate replacement thereof; and 
 a membrane attached to the second end of the first lens barrel such that the membrane is located externally of the second end of the first lens barrel and positioned to cover the vent hole, wherein the membrane has pores large enough to permit nitrogen gas to flow through the membrane and the vent hole. 
 
     
     
       2. The apparatus of  claim 1 , wherein the second end of the first lens barrel is covered by a circuit board and the membrane is located inwardly of the exterior threading on the first end of the first lens barrel along the radius of the first lens barrel. 
     
     
       3. The apparatus of  claim 2 , wherein the outer lens is attached to the first lens barrel with an air-tight seal. 
     
     
       4. The apparatus of  claim 1 , comprising:
 a circuit board positioned to cover the second end of the first lens barrel; and 
 an image sensor attached to the circuit board and positioned at the second end of the first lens barrel to receive light incident through the one or more inner lenses of the first lens barrel. 
 
     
     
       5. The apparatus of  claim 4 , wherein the first lens barrel is glued to the circuit board. 
     
     
       6. The apparatus of  claim 1 , wherein the membrane is hydrophobic. 
     
     
       7. The apparatus of  claim 1 , wherein the membrane includes pores of widths in a range between 5 micrometers and 60 micrometers. 
     
     
       8. The apparatus of  claim 1 , wherein the second lens barrel defines an inner channel, the additional inner lens located within the inner channel. 
     
     
       9. The apparatus of  claim 1 , wherein the outer lens is secured to an external surface of the second lens barrel. 
     
     
       10. The apparatus of  claim 1 , wherein the retaining ring is in direct contact with the outer lens. 
     
     
       11. An apparatus comprising:
 a first lens barrel having an inner channel extending from a first end of the first lens barrel to a second end of the first lens barrel, the first lens barrel including one or more inner lenses positioned within the inner channel; 
 a second lens barrel positioned within the first lens barrel and including an outer lens and an additional inner lens, the second lens barrel removable from the first lens barrel to facilitate replacement thereof; 
 a circuit board attached to the second end of the first lens barrel and having a side positioned to cover the second end of the first lens barrel, wherein the inner channel is open to the circuit board and the circuit board has a single vent hole extending linearly through the circuit board such that the single vent hole defines a non-tortuous path that extends from the inner channel to an opposite side of the circuit board; and 
 a membrane attached to the circuit board and positioned to cover the single vent hole, wherein the membrane has pores large enough to permit nitrogen gas to flow through the membrane and the single vent hole. 
 
     
     
       12. The apparatus of  claim 11 , comprising:
 an outer lens that is attached to the first lens barrel and positioned to cover the first end of the first lens barrel. 
 
     
     
       13. The apparatus of  claim 12 , wherein the outer lens is attached to the first lens barrel with an air-tight seal. 
     
     
       14. The apparatus of  claim 11 , comprising:
 an image sensor attached to the circuit board and positioned at the second end of the first lens barrel to receive light incident through the one or more inner lenses of the first lens barrel. 
 
     
     
       15. The apparatus of  claim 11 , wherein the first lens barrel is glued to the circuit board. 
     
     
       16. The apparatus of  claim 11 , wherein the membrane is hydrophobic. 
     
     
       17. The apparatus of  claim 11 , wherein the membrane includes polytetrafluoroethylene. 
     
     
       18. The apparatus of  claim 11 , wherein the membrane is waterproof. 
     
     
       19. An image capture device comprising:
 a lens assembly including:
 a first lens barrel defining a cavity and including one or more inner lenses to direct light onto an image sensor attached to a circuit board and located at one end of the cavity, the cavity connected to a space external to the lens assembly by a vent hole extending linearly through the circuit board to define a non-tortuous path, the first lens barrel including exterior threading to facilitate connection of a retaining ring thereto; and 
 a second lens barrel positioned within the first lens barrel and including an outer lens and an additional inner lens, the second lens barrel removable from the first lens barrel to facilitate replacement thereof; and 
 
 a membrane positioned to cover the vent hole, wherein the membrane has pores large enough to permit nitrogen gas to flow through the membrane and the vent hole. 
 
     
     
       20. The image capture device of  claim 19 , wherein the space external to the lens assembly is internal to a body of the image capture device that is attached to the lens assembly.